Protective system for safe disposition of a hypodermic syringe device

ABSTRACT

A device for protectively sheathing a syringe and hypodermic injection or body fluid withdrawal element, which device includes a tubular sheath having a syringe barrel reciprocably mounted within the tubular sheth for coaxial movement. The barrel carries a plunger for moving a liquid through a spout or tip on one end of the barrel. The sheath, near one of its ends, carries a locking element, and the barrel, adjacent its end through which liquid passes upon reciprocation of the plunger, carries a cooperating locking element which interlocks with that locking element carried by the sheath when the barrel is withdrawn into the sheath to a location where the barrel tip is totally encased and any hypodermic injection or fluid withdrawal element which is carried on the tip of the barrel is protected.

This is a continuation of copending U.S. patent application Ser. No.7/550,328 filed on 7/9/90 pending.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a device which locks the ejection tip of ahypodermic syringe and a hypodermic needle carried thereon within aprotective shield, so that the needle can be safely discarded, andunauthorized re-use thereof is prevented.

2. Brief Description of the Prior Art

In the medical knowledge and understanding of various communicablediseases of the present day, it is well understood that the blood maycarry viruses or microbial entities which are active instrumentalitiesin the transmission of disease from one individual to another. Bloodwhich is thus "contaminated" must therefore be limited in itssusceptibility to human contact outside the body of the carrier so thatthe exposure of medical personnel or others who may be in closeassociation with the carrier of the communicable disease is minimized.In situations, for example, where the carrier is a patient and themedical procedure being performed requires exposure to the patient'sblood, it may be important that no contact of the blood of the patientwith the physician or other medical personnel occurs.

One frequently performed medical procedure involves piercing the skin ofthe patient to administer hypodermic injections of medicaments ornutrients, or to extract body fluids for analysis and testing. Thisprocedure poses a risk of transmission of communicable disease throughthe contact of the blood or body fluids of the patient with medicalpersonnel, or the inadvertent introduction of a miniscule amount of suchblood or body fluids into the blood stream of such personnel (through ascratch, exposed abrasion or the like).

An especially intense concern has recently arisen in the case of thedisease called "acquired immune deficiency syndrome" (AIDS) because itis well known that this disease is transmitted with the blood of aninfected person, and because of the fact that the disease, withoutpresently known exception, is fatal when contracted. Because of therapid, near epidemic spread of the AIDS disease and the knowledge thatone source of contraction of the disease is contaminated blood, it hasbecome a great concern that hypodermic needles and syringes used fordrawing blood, or for injecting medicaments or the like into the body ofa patient for medical or dental purposes, be used only once, and thendisposed safely and with finality, so that personnel may notinadvertently use the same needle for a second injection, or forwithdrawal of body fluids, or may not become inadvertently andaccidentally scratched by the exposed point of such a once usedhypodermic needle, or contaminated by body fluids exposed upon thebarrel or tip of the syringe.

It is also understood, from the concerns of medicine with thetransmission of various social diseases, and with the arresting andreversal of the wide spread practice of drug abuse, that the repeateduse of inadequately cleaned hypodermic needles by persons who abusedrugs of the type which are taken intravenously and by subcutaneousinjection poses a real threat of the transmission of certain socialdiseases, including AIDS, from one person to another. Persons who areaddicted to the use of drugs taken intravenously generally utilizesyringes and hypodermic paraphernalia for accomplishing variousinjections of such drugs into the blood stream. Because of the frequentdisregard of such persons for the cleanliness or the source ofhypodermic needles and syringes used for practicing their habit, it ishighly desirable that hospitals, clinics and other places where greatnumbers of hypodermic syringes and needles are to be used and thendiscarded take great care in the disposal of these devices. Thesedevices should be discarded in a way such that they cannot be picked upand re-used by such persons who are careless in such use, and who maylack adequate funds or motivation to procure new and medically sterilesyringes for the purpose of practicing such drug injection habits.

Recently, strict rules and procedures have been placed in effect whichundertake to assure that hypodermic needles and syringes and hypodermicinjection devices used in hospitals and clinics are disposed of in a waywhich prevents their re-use, and assures that they are safe frominadvertent contact.

Various devices and apparatus have been proposed for securing and forshielding the tip and body of a syringe and hypodermic needle from viewand from contact prior to actual use. For example, in Gabriel U.S. Pat.No. 2,845,065, a flexible and resilient element in the form of a sleeveor tubular element is placed over the hypodermic needle carried at thelower end of the syringe barrel. This sleeve is forced, by contact withthe body, at the time of a hypodermic or subcutaneous injection, to movetoward the syringe barrel in a direction which allows the needle tobecome exposed, and to penetrate the body. Prior to this time, and evenat this time, the needle has not been visually perceptible, and mayremain invisible because of the extension of the sleeve to the point ofinjection, at which point the sleeve bears against the skin andsurrounds the point where the needle pierces the skin.

This device is, of course, constructed in this way primarily to preventthose who have a phobia about the use of needles for administeringhypodermic injections from being as alarmed or frightened as wouldotherwise be the case if the needle were in full view. Such devices,after functioning to hide the needle until the time of injection, can bereturned to a shielding position where the needle is again surroundedand obscured from view following the injection. The very nature of suchflexible and resilient sleeves which permit them to be forced back withlittle pressure from the body when a shot is to be given, and the sleevecontacts the body, also prevents such a sleeve from affording any verysignificant protection for the needle because such sleeve can be easilyforced back to a position where the needle can be inadvertentlycontacted, and can even be re-used if such is attempted.

Another device which is intended to hide from view the needle associatedwith the hypodermic syringe until the instant of injection is depictedand described in U.S. Pat. No. 2,571,653 to Bastien. In the Bastienpatent, a syringe is provided which is a conventional hypodermicsyringe, but which is fitted with a concealing tubular sheath fittedover one end of the barrel. The sheath is slidable along the barrelbetween two positions to which it is indexed by means of a small latchwhich projects through the side of the sheath and consecutively engagesa pair of grooves formed in the outer surface of the syringe barrel ataxially spaced locations. In the use of the Bastien syringe, the personwho is to administer an injection with the syringe initially fills thesyringe with a medicament to be injected, and then places the sheathover the lower end of the barrel so that the latch is engaged with thelower of the annular grooves formed around the barrel. The sheath atthis time obscures or prevents view of a needle carried on the lower endof the barrel.

When the injection is administered, the person administering theinjection pulls a handle of the sheath and pushes a handle of thebarrel, so that the two move relatively toward each other, thus causingthe sheath to move upwardly along the barrel until the latch enters thesecond groove. At this time the needle is exposed and the injection canbe given. This procedure is reversible so that the sheath can be re-setto an obscuring, or view-blocking position, if desired, thus permittingthe syringe to be re-used any number of times desired. The latch is madeso it can be easily popped in and out of either of the annular groovesin the barrel simply by the operator's finger pressure. The Bastiendevice therefore does not afford any significant protection againstre-utilization of the syringe and the needle which it carries, andagainst consequent contamination of any unauthorized users or personswho may inadvertently become scratched by the exposed needle.

Another deficiency of the Bastien device as a protective assembly whichcannot be easily moved to a position in which access can be had to theneedle is that the mechanism which effects the temporary latching isexposed on the outer side of the sheath, and can therefore be easilydestroyed or rendered inoperative by anyone. Little or no significantforce or strength is required to do so to effect the unlatching of thebarrel from the sheath.

A hypodermic syringe assembly which temporarily protects or covers theneedle of the syringe is shown in Bower U.S. Pat. No. 2,674,246. Here,however, the principal objective of the Bower hypodermic syringeconstruction is simply to conceal the needle from a patient until theinstant of injection. The concealing tubular member or guide whichsurrounds the needle is spring biased outwardly to a position where itwill hide the needle from view. Finger pressure on the barrel of thesyringe is sufficient, however, to overcome the bias of the spring, andto cause the needle to be extended out the end of the protective sleeveor tube and through the skin of the patient. There is therefore no safeposition which precluded unauthorized use of the needle, and indeed,merely dropping the device would apparently cause its spring to becompressed sufficiently to permit the needle to scratch the skin if itshould inadvertently fall against the leg or foot of a person.

Another manually operable syringe device which obscures or hides theneedle from view prior to use of the needle is that which is shown inSagstetter U.S. Pat. No. 4,664,653. The Sagstetter injection apparatusis, however, intended to be reusable, and the entire syringe unit can beremoved from the protective housing following the administration of theinitial injection. After such removal, the needle is covered only by aflexible, easily penetrable sleeve.

GENERAL DESCRIPTION OF THE PRESENT INVENTION

The present invention provides a system for protectively sheathing asyringe and hypodermic injection element, such as a hypodermic needle,which protective system includes a tubular sheath which has a syringebarrel reciprocably, coaxially and concentrically mounted within thetubular sheath for coaxial movement therewithin. The barrel reciprocablyreceives a plunger in conventional fashion, and the plunger isfunctional to eject a liquid from a spout or tip on one end of thebarrel.

The sheath, near one of its ends, carries a locking element, and thebarrel, adjacent its end through which liquid is ejected uponreciprocation of the plunger, is connected to a second and cooperatinglocking element. The latter locking element functions to interlock withthe first-described locking element carried by the sheath at a time whenthe barrel has been retracted or withdrawn into the sheath to a locationtherewithin where the barrel tip through which the liquid is ejected istotally encased within the sheath, and is protected by it. The interlockis such that it cannot be inadvertently, nor indeed easily, broken ordisplaced. The syringe and/or needle, protected in this way, cantherefore be discarded without fear of re-use or inadvertent scratchingor puncturing of the flesh of persons with whom it might otherwiseaccidentally come into contact.

An important object of the invention is to provide a protective systemor assembly which includes a protective tubular sheath which, followingthe administration of an injection, or the hypodermic or subcutaneousintroduction of a medicament into the body, or the withdrawal of a bodyfluid, can be used to render the syringe device completely inoperative,and to protect the syringe and/or any hypodermic injection device, suchas a needle, which it may carry, from inadvertent or careless contact byindividuals who may be in close proximity to the system. Further theprotective system or assembly permits discard or disposal of usedsyringes and needles without fear for their subsequent reuse byunauthorized personnel.

Additional objects and advantages of the invention will become apparentas the following detailed description of a preferred embodiment of theinvention is read in conjunction with a perusal of the accompanyingdrawings which illustrate such preferred embodiment.

GENERAL DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view partially in side elevation and partially inlongitudinal section of a protective device constructed in accordancewith the present invention. The device is illustrated at a time when thedevice is in a status in which it can be used for administering ahypodermic injection.

FIG. 2 is a view taken along line 2--2 of FIG. 1.

FIG. 3 is a view partially in section and partially in side elevation,similar to FIG. 1, but showing the protective device in a safe,throw-away status in which the hypodermic injection syringe assembly hasbeen withdrawn into the protective sheath and locked therein so as toprotect the hypodermic needle carried on one end of the syringe.

FIG. 4A is a view partially in section and partly in elevation, similarto FIG. 1, but having parts broken away, and illustrating a differentembodiment of the invention from that which is illustrated in FIGS. 1-3.The status of the protective system illustrated in FIG. 4A is that ofthe system at the time it is used for administering a hypodermicinjection.

FIG. 4B is a sectional view taken along line 4B--4B of FIG. 4A.

FIG. 4C is a view partially in section and partially in side elevationillustrating the protective system when it has been placed in itslocked, safe position suitable for discarding.

FIG. 5A is a partially sectional, partially elevational view similar toFIGS. 1 and 4A (with parts broken away), but illustrating yet a thirdembodiment of the invention.

FIG. 5B is a sectional view taken along line 5B--5B of FIG. 5A.

FIG. 5C illustrates the third embodiment of the protective system of theinvention as it appears when the device has been shifted to itsinterlocking, safe status, and is ready to be discarded following use.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

The protective system of the invention includes a protective tubularsheath 10 which has an open first end, hereinafter termed an upper end12, and a second or lower end 14 which has an opening 16 therethrough oflimited size for a reason hereinafter explained. It should be pointedout that the tubular sheath 10 can be constructed of plastic, of glassor metal, but regardless of the material of construction, is preferablytranslucent or transparent with windows, so that the interior of thesheath is visible so graduation indicia on the syringe barrel can beread.

In the embodiments of the invention which are illustrated and describedin the present application, the open upper end of the protective tubularsheath 10 carries a collar 20 which is fixed to the upper end 12 of thesheath in any suitable manner. In other embodiments of the invention nothere illustrated, the collar 20 can be formed integrally with the sheath10, such as where the sheath and collar are both molded of plastic, orsome other procedure is used to facilitate such unitary or integralconstruction. The collar 20 defines a radially inwardly extendingannular rib or flange 22 and an internal shoulder 24, with an annularlocking slot or groove 26 located therebetween. In the illustratedembodiments of the invention, the collar 20 defines an axially extendingannular slot 27 into which the upper edge of the sheath is received. Abeveled lip 29 defines the radially inner side of this slot.

Slidably and reciprocably disposed within the tubular sheath 10 forcoaxial movement within the sheath is an elongated barrel 28 which is ofhollow cylindrical construction. The cylindrical barrel 28 can beconstructed of plastic or glass, and is typified by the types ofconstruction conventionally used in present day medical syringes. Thebarrel 28 includes an open upper end 30 and a lower end portion 32. Itis generally characteristic of the barrels included in the protectiveassemblies of the present invention that they are provided with anopening in the lower end portion of the barrel adequate to permit theejection of the liquid therefrom, or the withdrawal of a body fluidthereinto, in the ordinary use and functioning of the barrel as asyringe for administering a hypodermic injection.

In the form of the invention which is here illustrated, the lower endportion 32 of the barrel 28 carries a generally frustoconically shapedend or closure plate 34 which terminates at its lower end or apex in aprotuberant nipple or fluid ejection tip 36 of a conventional type wellunderstood in the art. Secured to the nipple or tip 36 by frictionalengagement is a hypodermic injection or fluid withdrawal device, such asa hypodermic needle 38. The interfitting relationship of the needle 38to the barrel 28 is conventional and forms no part of the presentinvention.

At its upper end, the barrel 28 is provided with a radially outwardlyprojecting handle 40 which can be held between the forefinger and indexfinger when the protective assembly is in use. The handle 40 permits thebarrel 28 to be retracted within the tubular sheath 10 at a later timeduring the use of the device in a manner and for a purpose hereinafterdescribed. The handle 40 also allows the device to be utilized foradministering a hypodermic injection of a liquid beneath the skin in theadministration of medication, or to be used for the withdrawal of blood.The handle 40, when used in this respect, permits the barrel 28 to beheld while a plunger, designated generally by reference numeral 42, iscaused to undergo reciprocation relative to the barrel. The plunger 42includes an elongated, cylindrical piston element 44 which fits snuglybut movably within the barrel 28, and can be reciprocated within thebarrel for the purpose of ejecting or withdrawing a liquid through theopening in the lower end thereof and through the hypodermic injectiondevice or needle 38. The plunger 42 carries a disc-shaped thumb plate 46at its upper end to permit it to be pressed with the thumb into thebarrel 28 in a reciprocating motion at a time when the barrel is grippedbetween the forefinger and the index finger, using the handle 40.

The structure illustrated in FIGS. 1-3, and thus far described, isconventional and well understood in the art. The purpose of the presentinvention is to provide a syringe structure which can be used for itsconventional purpose in the hands of a qualified and authorized personfor performing a hypodermic operation, but which can then madeabsolutely safe for disposal with adequate safeguards and assurancesagainst any possible reuse by unauthorized personnel who may retrievethe hypodermic injection device after it has been discarded. The risksattendant to such retrieval and re-use are well understood in connectionwith the role that such activity plays in drug abuse, or simply withrespect to the inadvertent re-utilization of a syringe which may havebeen contaminated by prior use on another patient, unknown to medicalpersonnel who might inadvertently then subsequently utilize it in thecase of a second patient.

In order to provide the assurance against re-use which is a principalobject of the present invention to achieve, a locking element isconnected to the lower end of the barrel 28 and is designated generallyby reference numeral 50. The locking element 50 includes a generallyfrustoconical cap plate 52 which is fitted against and secured to, thefrustoconical closure plate 34 at the end of the barrel 28. At its outerperiphery, the frustoconically shaped cap plate 52 carries a pluralityof radially outwardly inclined and rearwardly bent fingers 54. Theposition of the fingers 54 is such that the fingers are located in asmall annular space between the outer periphery of the barrel 28 and theinner surface of the sheath 10. The fingers 54 are made of spring metalso that they are continuously resiliently urged against the insidesurface of the sheath 10 when the barrel 28 is reciprocated within thesheath. There is an inward loading of the fingers 54 in the radialdirection so that the fingers are compressed inwardly against theresilient bias of the metal tending to cause the fingers to springradially outwardly. Each of the fingers carries a small maleprotuberance 55 on the end portion thereof.

The locking element 50 functions in the manner best illustrated in FIG.3. After the hypodermic injection has been administered, or bloodwithdrawal completed, and it is desired to render the device safeagainst subsequent use, the tubular sheath 10 is held while the handle40 of the barrel 28 is used to retract the barrel into the sheath untilit reaches the position shown in FIG. 3. At this time, the lockingelement 50 carried on the lower end of the barrel 28 functions to lockthe barrel and the hypodermic injection device or needle 38 carried onthe end thereof at the illustrated position within the protectivetubular sheath 10.

The locking element 50 functions at this time by having the distended,radially projecting, rearwardly bent resilient fingers 54 slide past theflange 22 and then snap outwardly so that the male protuberances moveinto the female locking slot or groove 26 formed within the collar 20.The collar 20 is, of course, in one embodiment, secured to the upper endof the tubular sheath 10, or can be formed integrally therewith, and thelocking of the barrel 28 at the illustrated position by means of thelocking element 50 interengaging the locking slot 26 assures that theneedle 38, and indeed the syringe which includes the barrel 28 andplunger 42, cannot be re-used. The device is now safe to discard and thepossibilities of re-use are very substantially reduced. It is preferred,for some usages, to construct the tubular sheath 10 of a strong rigidmaterial, such as a high density, relatively thick plastic, or evenmetal, so that it cannot be crushed or broken in order to gain access tothe needle 38. It should also be pointed out that in some instanceswhere, for example, a blood sample is to be withdrawn, the lockingelement 50 may simply be secured to the needle 38, and not to the barrel28.

In FIGS. 4A-4C, a different embodiment of the invention is illustrated.For the reason that many of the parts shown in this embodiment are thesame as the parts shown in FIGS. 1-3, identical reference numerals willbe used for identifying these identical parts, and different and newreference numerals will be used only to identify parts which aredifferent in the modified embodiment.

Referring initially to FIG. 4A, a syringe protective device in the formof the modified embodiment is there shown as the device appears at atime when it is being used for administering a hypodermic injection, ora withdrawal of body fluid. The tubular sheath 10 again contains thegenerally cylindrical and tubular barrel 28 which can be reciprocatedwithin the tubular sheath after the syringe has been utilized. Thetubular sheath 10 includes, as previously described, an open upper end12 and a lower end portion 14 which defines a relatively small opening16 which is of a size which is adequate for a portion of the hypodermicinjection device or needle 38 to pass through in the manner hereinbeforedescribed.

At its upper end, the tubular sheath 10 carries an annular collar 20which, as previously explained, can be separately made in the mannerillustrated in the drawing, or, with more expensive fabricationprocedures, can be integrally formed with the tubular sheath 10, such asa mere extension of the remainder of the sheath. As in the priorembodiment, the annular collar 20 includes an annular flange or rib 22,and also defines a slot or groove between this rib and an internalshoulder 24. In the embodiment of the invention illustrated in FIGS.4A-4C, however, instead of a locking slot of the type heretoforedescribed as characterizing the embodiment shown in FIGS. 1-3 adifferently configured locking slot 58 is illustrated. The locking slot58 has a slight enlargement 58a adjacent its lower end in order to moreeasily accommodate a concavo-convex or bowed locking spring 60. Theconcavo-convex locking spring 60 has an upper end portion which bearsagainst the shoulder 24, and at its lower end carries a reverse bent toe60a. It will be perceived in referring to FIG. 4a that the bowed lockingspring 60 is fitted within the locking slot 58 in a manner such that theconvex side of the locking spring faces the outer surface of the barrel28. In fact, it is preferred to have the bowed locking spring 60 contactthe outer side of the barrel so as to perform a collateral function ofguiding the barrel through its reciprocating movement within the tubularsheath. It will also be perceived in referring to FIG. 4A that theconcave, radially outer side of the bowed locking spring 60 is spacedfrom the inner side of the locking slot 58 so that the locking springcan be forced into the intervening space and there accommodated when thelocking of the barrel in a safe position is accomplished as hereinafterdescribed.

A locking element is secured to the lower end of the barrel and isplaced over, and secured to, the closure plate 34. The locking elementis designated generally by reference numeral 64. The locking element 64includes a frustoconical plate 66 which is centrally apertured toaccommodate the extension of the nipple or spout therethrough. Thefrustoconical plate 66 extends outwardly to the outer peripheral edge ofthe frustoconical closure plate of the barrel 28, and is there securedto a peripheral, annular skirt 68 which projects axially along the outerperiphery 28 for a short distance. The skirt portion 68 will beperceived to be of lesser thickness than the width of the annulusbetween the barrel 28 and the inner surface of the tubular sheath 10,and it will further be noted that the skirt 68 terminates in a beveledor tapered edge 70 at its upper end. At circumferentially spacedintervals around the outer side of the skirt 68 of the locking element64, a plurality of wedge-shaped protuberances 72 are formed and projectout and bear against the inner surface of the tubular sheath 10.

At a time when the usage of the syringe to administer a hypodermicinjection has been completed, and it is desired to safely discard thesyringe and the needle carried on the lower end thereof, the barrel 28is again retracted into the tubular sheath 10 until the status depictedin FIG. 4C is achieved.

As the barrel 28 moves upwardly in the tubular sheath 10 as a result ofholding the sheath in one hand and retracting the barrel by the use ofthe handle 40 with the other hand, the wedge-shaped protuberances 72carried at circumferentially spaced intervals around the outer side ofthe skirt portion 68 will cause the bowed locking spring 60 to be forcedoutwardly within the locking slot 58. This movement will, in turn, causethe toes 58 carried thereon to spring inwardly to the positionillustrated in FIG. 4C in which position they cannot pass by, but ratherwill bear against, the upper surface of the annular flange or rib 22.The barrel 28 of the syringe is now locked in this position, and the endof the syringe barrel through which the liquid is ejected, and theneedle carried thereon, are both protectively hidden from view andlocked in a physically protected position in which contact outside ofthe protective sheath is not possible. Discard of the device with a highassurance against unauthorized re-use is therefore possible at thistime.

A third embodiment of the invention is illustrated in FIGS. 5A-5C.Again, like reference numerals have been utilized to denominate likeparts. In the embodiment of the protective device depicted in thesefigures, a different locking element 80 is provided at the lower end ofthe barrel 28. The locking element 80 is constructed of spring metal,and includes a frustoconical cap plate 82 which is centrally aperturedto accommodate the projection of the nipple or spout therethrough. Thecap plate 82 is secured to the barrel at this location. Thefrustoconical cap plate 82 carries a peripheral, axially extending,generally cylindrical skirt 84 which projects closely adjacent the outerperipheral wall of the lower end of the barrel. Parts of the skirt 84are then reverse bent to provide, at the axially upper end of the skirt,a series of locking flanges or tabs 86. These locking tabs 86 areresiliently deformed by the confining effect of the inner surface of thetubular sheath 10.

The locking tabs 86 are thus forced inwardly in resilient deformation sothat, at a time when the barrel 28 is retracted upwardly within thetubular sheath 10 to the position illustrated in FIG. 5C, the lockingflanges 86 snap outwardly into the locking slot or groove 26. When thisaction occurs, the lower end of the barrel 28 and/or the hypodermicneedle 38 are protected and guarded by the surrounding protectivetubular sheath 10 against inadvertent contact, and against re-use.

Although certain preferred embodiments of the invention have been hereindescribed, it will be understood that various changes and innovationscan be effected in the illustrated and described embodiments withoutdeparture from the basic principles upon which the invention is based.Changes and innovations of that type which thus do not depart from thebasic principles of the invention are deemed to be circumscribed by thespirit and scope of the invention, and to be within the protection ofthe patent to be issued hereon, except insofar as such protection isprecluded by any limits necessarily placed upon the construction andinterpretation of the claims.

What is claimed is:
 1. A protective assembly for preventing contact withthe needle of a needle-carrying syringe used to perform hypodermicinjections or to withdraw body fluids into the syringecomprising:elongated tubular protective sheath means including a tubularsheath having a first open end and having a second end defining anopening therethrough; a syringe device adapted for attachment of ahypodermic needle thereto, said syringe device comprising:a hollowcylindrical barrel extending through the first open end of said tubularsheath and slidably mounted coaxially within said sheath for relativeaxial movement between the barrel and said sheath, said hollowcylindrical barrel including:an open, plunger-receiving first end; and asecond end portion having a tubular tip of reduced diameter relative tothe diameter of the open, first end of said barrel, said second endportion of said barrel being located at least partially within saidsheath, and said first end of said barrel being located outside of saidsheath and spaced from said first open end of said sheath; a movableplunger projecting into the open, first end of said cylindrical barreland fitting slidably within said barrel to function as a piston suitablefor ejecting a fluid from said barrel through said tubular tip, ordrawing a fluid through said tip into said barrel for sample takingpurposes; locking means on the outer side of said barrel and around saidtubular tip for cooperatively interlocking with said tubular sheath in aretracted position of the barrel in which said tubular tip is withdrawnwithin said sheath, and said barrel has been moved relatively from saidsecond end of said sheath means toward said first open end thereof, saidlocking means slidably engaging said tubular sheath for slidably guidingthe relative movement between said sheath and said barrel, said lockingmeans on the outer side of said barrel and around said tip comprising:aplurality of radially deformable resilient fingers carried on saidbarrel at circumferentially spaced intervals around the outer peripheryof the barrel, said fingers bearing resiliently against the innersurface of said sheath and being configured to facilitate reciprocatingsliding movement of said barrel in said sheath by bearing against theinterior of said tubular sheath, each of said radially deformableresilient fingers comprising a protuberant male locking end portion; andmeans on the tubular sheath adjacent its open end for interlocking withthe resilient fingers of said locking means on the outer side of saidbarrel when said barrel is moved upwardly in said sheath to saidretracted position, said interlocking means on said tubular sheathcomprising at least one female opening for receiving the male lockingend portion of at least one of said resilient fingers of said lockingmeans.
 2. The protective assembly of claim 1 wherein said female openingis a groove into which said protruberant male locking end portions ofsaid resilient fingers snap to effect said interlocking.
 3. Theprotective assembly of claim 1 wherein said locking means is a separatestructural element from said barrel and from said tubular sheath.
 4. Aprotective assembly for preventing contact with a needle used on ahypodermic syringe for injecting fluids into the body or for withdrawingfluids from the body comprising:an elongated tubular protective sheathmeans including a tubular sheath having a first open upper end and asecond lower end portion having an opening therethrough; a hypodermicsyringe device comprising:a hollow tubular barrel extending through theopen first end of said tubular sheath and slidably mounted coaxiallywithin said sheath for axial movement relatively between the barrel andsaid sheath, said barrel including:an open, plunger-receiving upperfirst end; and a second lower end portion having a tubular tip ofreduced diameter relative to the first end of said barrel, said secondend portion of said barrel being located predominantly within saidsheath with the tip thereof aligned with the opening through the lowerend portion of said tubular sheath whereby a needle carried thereon canproject through, and move through, said opening, said first end of saidbarrel being located outside of said sheath and spaced from said openupper end of said sheath; a movable plunger projecting into the open,first end of said tubular barrel and fitting slidably within saidtubular barrel to function as a piston suitable for ejecting fluid fromsaid barrel through said tubular tip, or for drawing fluid through saidtubular tip into said barrel; locking means on the outer side of saidbarrel around said tubular tip for cooperatively interlocking at least aportion of said hypodermic syringe device within said protective sheathin a retracted position in which said tubular tip is withdrawn withinsaid sheath, and said barrel has been moved relatively axially withinsaid sheath means further including:a collar formed integrally with saidsheath adjacent the open upper end thereof and guidingly contacting andengaging the outer periphery of said tubular barrel as said tubularbarrel moves slidably and coaxially within said tubular sheath; andmeans carried on said tubular sheath adjacent the open upper end of saidtubular sheath for interlocking with said locking means when said barrelis moved upwardly in said sheath means to said retracted position. 5.The protective assembly of claim 4 wherein said locking means comprisesa plurality of radially deformable resilient fingers mounted adjacentthe lower end portion of said barrel and bearing resiliently against theinner surface of said sheath, and each including a protuberant malelocking end portion.
 6. The protective assembly of claim 5 wherein saidinterlocking means carried on said tubular sheath comprises at least onefemale opening adjacent said collar for receiving at least one of saidprotuberant male locking end portions of two of said radially deformableresilient fingers.
 7. The protective assembly of claim 4 wherein saidlocking means is a separate structural element from said barrel and fromsaid tubular sheath.